The present invention generally relates to wafer edge exposure and, more particularly, to an apparatus for and a method of wafer edge exposure.
In the manufacturing of semiconductor products, a wafer edge exposure (WEE) process may be employed for exposing a photoresist film on an edge portion of a wafer so that undesired photoresist may be removed during a subsequent developing process. Generally, an apparatus for WEE processing may be installed in a tracker and equipped with a single light source.
FIG. 1 is a schematic diagram of an apparatus 70 for wafer edge exposure apparatus in prior art. Referring to FIG. 1, the apparatus 70 may include a light source 71, a reflector 72, a collective lens 73 and a light-shielding mask 74 with a slit 75. During a WEE process, an edge portion WE of a wafer “W” is exposed to light emitted from the light source 71 via the reflector 72, the collective lens 73 and the slit 75 of the light-shielding mask 74.
Such apparatus with a single light source, however, may not be able to properly expose an undesired photoresist film on a wafer edge in advanced semiconductor manufacturing as device patterns are increasingly reduced in size. For example, the light source may emit light composed of multiple light components of different wavelengths in a relatively large bandwidth, which may result in photoresist pattern deformation or peeling, especially in the manufacturing of down-sized semiconductor products. It may therefore be desirable to have an apparatus for and a method of wafer edge exposure.